Life expectancy has risen substantially over the past century, but people and populations do not all experience the same lifespan. This lesson explores what life expectancy means, why average longevity has increased, and how social, economic, health, and demographic factors contribute to differences.
Life expectancy is the average age to which members of a species or a defined population are expected to live. It is a statistical measure, not a promise about how long any particular person will live. A population’s average can be affected by many conditions, including infant mortality, disease, living conditions, and access to health care.
All flashcards
Life expectancy
The average age to which members of a species or defined population are expected to live; it is not an individual guarantee.
Hormonal stress theory
The proposal that prolonged exposure to stress hormones, such as cortisol, contributes to age-related health problems.
Free radical theory
The proposal that damage from unstable oxygen molecules accumulates and contributes to some age-related health problems.
Wear-and-tear theory
The proposal that unrepaired damage accumulates through bodily use, though it does not fully explain aging.
Neuroplasticity
The brain's ability to change in response to challenges or new experiences.
Quiz questions
Which description distinguishes primary aging from secondary aging?Answer: Primary aging involves natural changes not accelerated by disease; secondary aging is worsened by disease, lifestyle, or environment.
What is the Hayflick limit?Answer: The approximate number of times many cells can divide before division stops.
Which feature is characteristic of age-related macular degeneration?Answer: Damage to the macula that affects central vision, often while peripheral vision remains.
Which pattern is typical of presbycusis?Answer: High-pitched sounds are often affected before lower-pitched sounds.
How does respiratory function generally change in later adulthood?Answer: Reduced lung capacity and a weaker cough can make breathing and clearing particles less efficient.
Based on Lifespan Development by Diana Riser, Rose Spielman, David Biek (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.